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[SOLVED] [1.12] Set block light based on redstone input


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I'm trying to make a simple analog lamp, where the light output equals the max redstone input. I thought this would be simple, but it's not working. This is the relevant code, inside the block class:


	public int getLightValue(IBlockState state, IBlockAccess world, BlockPos pos) {
		if (world instanceof World) {
			World theWorld = (World) world;
			return theWorld.isBlockIndirectlyGettingPowered(pos);
		return 0;

	public void observedNeighborChange(IBlockState thisState, World world, BlockPos thisPos, Block changedBlock,
			BlockPos changedBlockPos) {
		world.setLightFor(EnumSkyBlock.BLOCK, thisPos, world.isBlockIndirectlyGettingPowered(thisPos));


Some debug output shows that the observedNeighborChange() method is being called correctly, when there's a block state change next to the lamp, and that isBlockIndirectlyGettingPowered() is returning the appropriate redstone signal strength.

Yet the block never lights up. Why not?


*Update* After more testing, it seems like the block light *is* getting set properly, but only after I exit the world and reload it. I thought checkLight() was supposed to update the light levels; if it's not, what do I need to call to update the light levels without relogging?

*UPDATE 2* I fixed it! As it turns out, you need to change the block state for Minecraft to actually update the lighting. Even calling setBlockState with the current state won't work; it needs to be a new block state. So I added a "power" property and set power equal to the redstone input, then I change the blockstate whenever the neighbor changes and it all works fine.

Edited by IceMetalPunk
Solved it myself

Whatever Minecraft needs, it is most likely not yet another tool tier.

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